Rigid Foam Insulation Over Wood Siding

We have a historic house that is undergoing a deep energy retrofit with rigid insulation being applied to the outside and then strapping and new siding.

Rigid foam insulation over wood siding.

The foam on the outside keeps the wood frame inside the wall warm and dry in. It seems this will create some nice air pockets which be. Readers are constantly asking if the rigid insulation is supposed to be installed over the building wrap or vice versa. Many houses built today have a double wall type of insulation with fiberglass batts fastened between the studs on the inside and rigid foam board over.

When installing wood siding over rigid foam sheathing you must protect the siding from moisture and heat buildup and use proper nailing. Is replacing wood siding with vinyl and. Moisture protection and heat buildup. Wood siding including cedar siding should be installed over an air space regardless of the type of sheathing used.

Well call me half hazard. He would like to keep it on and simply put the new rigid insulation over the siding. Plus rigid foam insulation applied over the outside walls. This is especially true if the wall is filled with fiberglass batt insulation.

What are the risks of installing cedar siding directly over foil faced rigid foam insulation should tar paper or housewrap be used as well. Gypsum sheathing up to 1 inch thick the foam sheathing and other non nailable substrates do not have nail holding capacity. Cover the house walls with 4 by 8 foot sheets of rigid foam insulation typically 1 2 to 1 inch thick nailed to wood sheathing with 1 1 2 inch broad headed galvanized nails every 16 to 18 inches. Always follow the manufacturer s instructions for installing rigid foam insulation.

The nails have a plastic cap that keeps them from damaging the foam. With foam sheathing an air space is essential both to reduce the siding s water uptake and to provide a. Of course i did this all knowing my warranty would be void. It adds up to a robust system.

Last year i installed lp lap smart trim shingles and the 4x8 sheets of lp with batts all over 3 of continous xps foam using fern strips. How should wood siding be installed over rigid foam insulation. Lp siding with fern strips over insulation. Since foil faced foam is a moisture barrier it should be used with a continuous film vapor retarder on the inside wall.

One of the most asked questions on our site is related to this article. The contractor has ripped off a few layers of asphalt siding and is now down to the original siding. Siding over rigid foam. When applying james hardie siding directly over the combined thickness of foam sheathing continuous insulation and other non nailable substrates e g.

Rigid foam over building wrap. Some people use roofing nails but if a strong gust of wind gets under the siding it may not hold.